Formula Conditional line chart

This chart displays a line that
changes colour depending on whether it is above or below a control line.
It is based on a xy-scatter chart.

The formula calculates all the intersections
and then the sorted values are plotted using 2 series.

Full credit goes to Dave Curtis, a forum member at
OzGrid. who provided the
formula to calculate the intersections.

I was able to add the formula to
dynamically sort the resulting values.

Update 16th February 2008:
Apollo Huang, a fellow MVP from China, pointed out a flaw in my sorting
formula, which was picking up incorrect cell values. I have incorporated
his formula revision in to the download.

The download
contains data based on the RAND function so will generate new values
automatically.